I have been in contact with the MSI Tech support but they didnt have a clue. Here is the thread: I Can't Access Bios After CPU upgrade. System description Part Number: ms-7025 CPU: AMD FX-57 Memory: 2x1GB PC3200 400MHZ SAMSUNG Operating System: Windows XP Pro SP2 Question Hi, I just upgraded my CPU from a FX-53(Clawhammer) to an FX-57(San Diego) on a K8N Neo2 PLATINUM (ms-7025, Bios version: 1.D0) and I can't access the bios on Startup. When the motherboard logo appear, I press DELETE to access BIOS but all it do is bringing me to a black screen with a flashing underscore(_) on the upper left screen and it hang there. If I press TAB on the motherboard logo, it brings me to the POST then a message appear on the lower screen: CMOS CHEKSUM ERROR - LOADING DEFAULTS, then it bring me to the same black screen. If i boot the computer without touching any buttons, it start windows and run perfectly. The system runs fine as long I don't want to go in the BIOS SETUP. But I want to access the BIOS! Please help me!!! Julien techsupport Sep,21,2007 09:35:43 Can you try clear the CMOS by remove the power cord then reset the jumper on the board and try again? Thanks! 3691julien Sep,21,2007 09:40:41 I already did did It. It did nothing. 3691julien Sep,21,2007 12:07:24 I cleared the CMOS before putting in the new CPU and two times after that. I though that could be the problem too but its not. I even reflashed the bios but it didnt do anything. techsupport Sep,21,2007 14:07:41 Can you try with one memory stick install into DIMM slot close to CPU socket. if board support adjustable memory vcore apply manually to 2.0V. Also, are you using PS/2 keyboard? Please try to disconnect all the USB devices and attach PS/2 keyboard then clear CMOS and test again. If its ok, please go to BIOS and enable "USB Legacy Support", re-test. Thanks! 3691julien Sep,24,2007 07:52:20 I just tried that this weekend and it didn't work. I can't enter the BIOS setup so I can't change voltage or anything inside it. Even with the PS/2 keyboard... Could it have something to do with my power supply not providing enough power, because when I unplug the power cable and replug it and flip the power switch ON, Its making a small weird hissing sound and when I press the power button, All the fans and everything start for about 1 or 2 seconds then it dies. Even if I press the power button again, nothing happen, I have to unplug the power cable and replug it to try again. It can "stall" like that for 2-3 times.Then when it start, if I don't unplug the power cable, it will start fine everytime. I know a bit about computers but this is gaving me a headache... I aslo check if the battery was good, and its still have a lot of power. Please help me!! Julien techsupport Sep,24,2007 09:31:08 Did you try using another PSU to test your system if you said that there is something wrong with your PSU? Also, what is your PSU spec? Thanks! 3691julien Sep,24,2007 12:13:16 I just changed my : The Best Power 500AT to a Okia 550ATX. At first it did "stall" two times making a small beep when doing so but after, it did start great and never stalled back. I tried 4 times after that unplugging the power cable and it didnt stall. But I still can't access the BIOS SETUP, its still the black page with a flashing underscore that appear... It still show:CMOS CHEKSUM ERROR - LOADING DEFAULTS... I checked for any short circuit that might bew occuring in the case but I didnt saw anything... Its a weird problem... techsupport Sep,24,2007 13:12:18 Yes, its a weird problem that you can not access BIOS. Please try to reset the BIOS by find the 3-pin jumper connecting the 1st and 2nd pin. Move it to connect the 2nd and 3rd pin and push the POWER button on your PC. Return it to its position. Make sure you computer is unplugging before doing this. Thanks! 3691julien Sep,25,2007 07:31:54 I did it, didnt help... I even changed the battery yesterday to make sure it wasnt that the problem, but it didnt help. Do you have a BIOS version that would fix this? this problem is a bit frustating... Please help me... techsupport Sep,25,2007 09:30:02 Please apply for the RMA service and send it back to us to inspect. If we can not find out what is the problem is then we will ship you back the replacement. Thanks and sorry for any inconvinence. I need help!